OP:Attack on Titan: It's just plain fun to watch. it's so "Aw snap get ready for some good old fashioned Titan killing", it totally pumps you up for the episode. Good stuff.Majestic Prince: Oh man, I couldn't stand Majestic Prince, but I'd happily watch the show just for the opening. The song is so pretty and the animation's pretty nice, too. A major stand out.Karneval: The animation is so clustered (much like the show it's self, actually), but the songs nice.

ED:
Honestly, I don't pay much attention to endings, but Karneval, Devil Survivor 2, and Aku no Hana all come to mind for good songs. Attack on Titan had some interesting animation to it's ending, but I didn't think much of the song.

Railgun 2's OP, just hearing the OP instead of watching it, just to avoid spoilers.

Still trying to find a way to watch the english dub somewhere like funimation (But I still need a elite subscription).

When will there be new anime on netflix?

Hulu might add the Railgun dub eventually(I'm watching it now on DVD it's really not that bad considering most dubs are). Netflix just re-licensed a bunch of anime but I'm pretty sure Funi titles aren't among them.

I really like attack on titan's OP and Gargantia's and Valvrave's and Majestic Prince and Yuyushiki and mushibugyo I don't like END songs much as they are generally so much more serious sounding songs but they aren't like songs that start most series and I probably wouldn't try to add the artist of endings to my pandora playlist lol

So far Aku no Hana OP - utterly at odds somehow with the programme, and ED - skin-crawlingly terrifying, are of the few really sticking in my mind. Other than AoT OP and ED of course (both animation and songs beautiful for that one).

I'm sure others will grow on me, although I must say that I find the theme songs to new anime quite difficult to get into due to the lack of subs. With a few exceptions (e.g. Amnesia and all Space Brothers OP and EDs). I know that CR has to get the rights to translate the songs (bizarre!), so that's why they don't have them, but I find it odd that you can't even find fan subbed versions.